32 
Indiana University Studies 
Subgenus Dolichostrophus 
11. Antennse with 13 segments (14 only in rare individuals) ; 
leaf and stem galls always polythalamous ; anther and 
cupule galls monothalamous. 12 
Antennae regularly with 14 segments, the third hardly 
half again as long as the fourth ; male largely black, with 
the third antennal segment not lengthened, only slightly 
curved ; galls monothalamous on both leaves and anthers ; 
transcontinental. N. dubius 
a. Mouthparts piceous yellow ; legs light yellow and 
brownish ; northeastern IJ.S. ; on Q. alha. 
var. clarkese 
b. Mouthparts rufous; legs golden yellow except the 
piceous coxse; central California; on Q. lobata. 
var. digressus 
c. Mouthparts light rufous; legs wholly golden yellow; 
northeastern U.S. ; on Q. stellata. var. dubius 
12. Thorax not more than half again as long as wide ; cubitus 
reaching the basalis near the midpoint. 13 
Thorax elongate, almost twice as long as wide; cubitus 
reaching the basalis below the midpoint; male brownish 
yellow; the galls are swellings 3. mm. or less high, lying 
along the stem; all of North America; on chestnut oaks. 
N. rileyi 
a. Abdomen piceous brown ; areolet distinctly small ; 
length to 1.7 mm.; gall larger; Texas, Oklahoma; on 
Q. Prinus. var. atripleurae 
b. Abdomen piceous brown; areolet moderately small; 
length to 1.7 mm.; gall large; Central Texas; on Q. 
Muhlenbergii. var. mutatus 
c. Abdom.en black ; areolet large ; length to 2.0 mm. ; gall 
larger; Middle West; on Q. prinoides. var. rileyi 
d. Abdomen piceous brown; areolet large; length to 1.7 
mm. ; gall smaller ; northeastern U.S. ; on Q. prinoides. 
var. thompsoni 
e. Abdomen piceous brown; areolet rather small; length 
2.0 mm. ; gall very small ; more eastern Colorado ; on 
Q. Gambelii. var. virgens 
